It is known to provide a tire pressure monitoring system for a vehicle to provide an output or alert to a driver or occupant of the vehicle when a low pressure situation occurs in one or more of the vehicle tires. Such systems often include a pressure sensor in each tire that broadcasts a signal to a control in the vehicle. The control may process the signal and generate a signal to a display for displaying or actuating a display of an icon that indicates to the driver or occupant that a low pressure condition exists. For reasons of economy, such alerts are typically shown iconistically, with no physical, numerical readout of the tire pressure.
Such tire pressure monitoring systems are regulated by the National Highway Traffic Safety Administration (NHTSA), such as by 49 CFR Section 571.138, which is hereby incorporated herein by reference. The regulations mandate that the icon or display comes on or appears if a significant under-inflation situation occurs, such as when one or more tires has a pressure of less than 25 percent of the manufacturer's cold inflation pressure. The icon may be initially flashed upon detection of the under-inflation condition and/or upon startup of the vehicle when such an under-inflation condition exists, and may be continuously illuminated after a period of time of flashing.